454 Transactions. —Geology. 
river, never filled up to the height of the plains at their reduced level, and, 
on the land being re-elevated, it remained as the river channel and was 
gradually cut down into the gorge. 
There are several quite independent reasons for thinking that the sea 
has flowed over the Canterbury Plains; but these I need not repeat here as 
they will be found in the Transactions of the New Zealand Institute, vol v., 
p. 987, and in the Geological Reports for 1873-74, pp. 56-58. 
On the other hand two objections may be fairly raised to my hypothesis. 
First, that there is no trace of flattened sea-shingle; and second, that there 
are no marine fossils. With regard to the first objection we must remember 
that the form of beach shingle depends a good deal on the structure of the 
rocks from which it has been derived, and that if the rocks have not a 
schistose or slaty structure the shingle must remain for a considerable time 
within reach of wave action before it can acquire a flattened form. This 
objection may therefore be got over by supposing that subsidence and re- 
elevation were continuous and tolerably rapid. The second objection rests 
only on negative evidence as no fossils of any kind have been found. It is 
of no value here where the beds, except quite the upper portions, are allowed 
to be of fluviatile origin, and are composed of shingle through which water 
easily percolates ; for under these circumstances all calcareous remains are 
soon dissolved. I think, therefore, that the objections to the hypothesis 
here put forward are of far less weight than the objections to any other 
hyphothesis; but, whatever value may be attached to the argument, it is 
certain that no theory of the formation of the Canterbury Plains can be 
satisfactory if it fails to account for the lower gorge of the Waimakariri. 
Arr. LIL. —Recent Discoveries in the Neighbourhood of Milford Sound. 
By Donatp SurmerLanD. Communicated by Alexander McKay. 
(Read before the Wellington Philosophical Society, 15th August, 1884.} 
Plate XLII 
Messrs. SurmerLawD and McKay, well known as explorers and prospectors 
of Western Otago, haye for some years past devoted their attention to the 
vicinity of Milford Sound, and from their principal camp at the head of that 
Sound, they have explored the country in almost every direction. Sur- 
rounded as Milford Sound is by impassable mountains to the east and north, 
the valley of the Arthur River lying southward of the head of the Sound 
presents the only hopeful route by which to reach the Lake District of 
Otago. The eastern branch of the Arthur River, above Lake Abraham, was 
explored to its source, but no outlet was discovered in this direction, the 
